[BUG][Serverless][8.15 & 8.16] Refresh the Optimizing anomaly results topic

[nastasha-solomon]

Contributes to #3998 by refreshing content and fixing style issues in the ESS and Serverless versions of the "Optimizing anomaly results" topic.

• ESS preview
• Serverless preview

[github-actions]

A documentation preview will be available soon.

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• Rebuild this PR and all Elastic docs: run docs-build rebuild

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[mergify]

This pull request does not have a backport label. Could you fix it @nastasha-solomon? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• v7.x is the label to automatically backport to the 7.x branch.
• v7./d./d is the label to automatically backport to the 7./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

[mergify]

This pull request is now in conflicts. Could you fix it @nastasha-solomon? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b issue-3998-refreshes-opt-anomaly-docs upstream/issue-3998-refreshes-opt-anomaly-docs
git merge upstream/main
git push upstream issue-3998-refreshes-opt-anomaly-docs